Electrocardiographic Parameters as Predictors of Response to Cardiac Resynchronization Therapy

Abstract

INTRODUCTION:Although strict selection criteria are used to select patients for cardiac resynchronisation therapy, up to 30% of patients do not have a positive clinical response.PATIENTS:A total of 102 consecutive patients who had biventricular pacemaker/defibrillator (CRT-P or CRT-D) implanted were enrolled in this prospective observational study.RESULTS:During the average follow-up period of 24.3 months 5 patients died and 17 (16.7%) patients were hospitalised with the symptoms of heart failure; 75 (73.5%) patients were responders based on the previously defined criteria. Responders in the group of LBBB patients kept the significant difference in a computed variable (S1 + R6) - (S6 + R1) and R6/S6 ratio. Responders in non-LBBB patients kept the significant difference only in the height of R waves in V6. The R6/S6 ratio tended to be higher, but it did not reach a statistical significance.CONCLUSION:None of the tested ECG parameters stands out as an independent predictor of response to cardiac resynchronisation therapy, but some of them were different in responder-compared to the non-responder group. The amplitude of R wave in V6, higher R/S ratio in V6 and higher computed variable (S1 + R6) - (S6 + R1) may predict the likelihood of response to CRT therapy in both LBBB-patients and non-LBBB patients.

Useful Electrocardiographic Signs to Support the Prediction of Favorable Response to Cardiac Resynchronization Therapy

“…A simultaneous delay in the activation of the right ventricle (for example because of a right ventricular pressure overload and enlargement), or posterosuperiorly pointing to late left ventricular activation because of biventricular enlargement [39], or an apical location of a branch of the left posterior fascicle [40], are suspected. Poposka et al [41] also found that a larger R/S amplitude ratio in V6 is a predictor of CRT response in both LBBB and non-LBBB patients. Another similar marker which may predict CRT response in LBBB is the lead one ratio (LOR) [42].…”

Synchronizing Beats: From Theory to Advances and Insight in Cardiac Resynchronization Therapy

“…While no single ECG parameter could predict CRT response on its own, yet specific parameters did demonstrate a difference between responders and nonresponders. In particular, an increased amplitude of the R wave in lead V6, an elevated R/S ratio in the same lead, and the derived figure (S1 + R6) − (S6 + R1) may suggest a greater likelihood of response in both LBBB and non-LBBB patients [67].…”

“…LBBB vs. Non-LBBB Patients: Patients with LBBB typically have a more dyssynchronous contraction pattern, and CRT aims to correct this dyssynchrony. Therefore, parameters that reflect the extent of dyssynchrony in LBBB patients may be more predictive of CRT response in this group compared to non-LBBB patients (Figure 12) [67,71].…”

Re‐evaluating the electro‐vectorcardiographic criteria for left bundle branch block

“…The R6/S6 ratio tended to be higher, but it did not reach a statistical significance (Poposka et al, 2018). Bear et al evaluated the sensitivity of body surface mapping and ECG imaging to detect electrical dyssynchrony noninvasively, and experimentally using Langendorff isolated perfused in pig hearts with LBBB induced through ablation.…”